The overall energy homeostasis of a mammalian system requires a high degree of regulation to ensure the availability of the appropriate substrate at the appropriate time. Plasma glucose levels rise during the post-prandial state, to return to pre-prandial levels within 2-3 hours. During these 2-3 hours, insulin promotes glucose uptake by skeletal muscle and adipose tissue and decreases the release of free fatty acids (FFA) from adipocytes, to ensure that the two substrates do not compete with each other. When plasma glucose levels fall, an elevation in plasma FFA is necessary to switch from glucose to fat utilization by the various tissues.
In individuals with insulin resistance, FFA levels do not fall in response to insulin, as they do in normal individuals, preventing the normal utilization of glucose by skeletal muscle, adipose and liver. Furthermore, there is a negative correlation between insulin sensitivity and plasma FFA levels.
Hormone-sensitive lipase (HSL) is an enzyme, expressed primarily in adipocytes, that catalyses the conversion of triglycerides to glycerol and fatty acids. It is through the regulation of this enzyme that the levels of circulating FFA are modulated. Insulin leads to the inactivation of HSL with a subsequent fall in plasma FFA levels during the post-prandial state, followed by the activation of the enzyme when the insulin concentration falls and catecholamines rise during the post-absorptive period. The activation of HSL leads to an increase in plasma FFA, as they become the main source of energy during fasting.
The activation-inactivation of HSL is primarily mediated through the cAMP-protein kinase A and AMP-dependent kinase pathways. There are compounds like nicotinic acid and its derivatives, that decrease the activation of HSL via these pathways and cause a decrease in lipolysis that leads to a reduction in the FFA levels. These drugs have a beneficial effect in the utilization of glucose and in the normalization of the excess triglyceride synthesis seen in patients with elevated FFA. However, since these pathways are used by other processes in the body, these drugs have severe side effects.
We have found compounds that specifically inhibit the lipolytic activity of HSL and lead to a decrease in plasma FFA levels. These compounds can be used to treat disorders where a decreased level of plasma FFA is desired, such as insulin resistance, syndrome X, dyslipidemia, abnormalities of lipoprotein metabolism.
One object of the present invention is to provide compounds and pharmaceutical compositions that inhibit the lipolytic activity of HSL. A further object is to provide compounds which have good pharmaceutical properties such as solubility, bioavailability etc.
Definitions
The following is a detailed definition of the terms used to describe the compounds of the invention.
“Halogen” designates an atom selected from the group consisting of F, Cl, Br and I.
The term “C1-6-alkyl” in the present context designates a saturated, branched or straight hydrocarbon group having from 1 to 6 carbon atoms. Representative examples include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, isohexyl and the like.
The term “C2-6-alkyl” in the present context designates a saturated, branched or straight hydrocarbon group having from 2 to 6 carbon atoms. Representative examples include, but are not limited to, ethyl, n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, isohexyl and the like.
The term “C1-6alkoxy” in the present context designates a group —O—C1-6-alkyl wherein C1-6-alkyl is as defined above. Representative examples include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentdxy, tert-pentoxy, n-hexoxy, isohexoxy and the like.
The term “C3-8-alkoxy” in the present context designates a group —O—C1-6alkyl wherein C3-8-alkyl is a saturated, branched or straight hydrocarbon group having from 3-6 carbon atoms. Representative examples of C3-6-alkoxy include, but are not limited to, n-propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy, tert-pentoxy, n-hexoxy, isohexoxy and the like.
The term “C2-6-alkenyl” as used herein, represent an olefinically unsaturated branched or straight hydrocarbon group having from 2 to 6 carbon atoms and at least one double bond. Examples of such groups include, but are not limited to, vinyl, 1-propenyl, 2-propenyl, allyl, iso-propenyl, 1,3-butadienyl, 1-butenyl, hexenyl, pentenyl and the like.
The term “C3-10-cycloalkyl” as used herein represents a saturated mono-, bi-, tri- or spirocarbocyclic group having from 3 to 10 carbon atoms. Representative examples are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclo[3.2.1]octyl, spiro[4.5]decyl, norpinyl, norbonyl, norcaryl, adamantyl and the like.
The term “C3-8-heterocyclyl” as used herein represents a saturated 3 to 8 membered ring containing one or more heteroatoms selected from nitrogen, oxygen and sulfur. Representative examples are pyrrolidyl, piperidyl, piperazinyl, morpholinyl, thiomorpholinyl, aziridinyl, tetrahydrofuranyl and the like.
The term “aryl” as used herein represents a carbocyclic aromatic ring system being either monocyclic, bicyclic, or polycyclic, such as phenyl, biphenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, indenyl, pentalenyl, azulenyl, biphenylenyl and the like. Aryl is also intended to include the partially hydrogenated derivatives of the carbocyclic aromatic systems enumerated above. Non-limiting examples of such partially hydrogenated derivatives are 1,2,3,4-tetrahydronaphthyl, 1,4-dihydronaphthyl and the like.
The term “aryloxy” as used herein represents an aryl which is linked via an oxygen atom, e.g. phenoxy, 1-naphthyloxy, 2-naphthyloxy and the like.
The term “heteroaryl” as used herein represents a heterocyclic aromatic ring system containing one or more heteroatoms selected from nitrogen, oxygen and sulfur such as furyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, pyranyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, 1,2,3-triazinyl, 1,2,4-triazinyl, 1,3,5-triazinyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, tetrazolyl, thiadiazinyl, indolyl, isoindolyl, benzofuranyl, benzothiophenyl (thianaphthenyl), indazolyl, benzimidazolyl, benzthiazolyl, benzisothiazolyl, benzoxazolyl, benzisoxazolyl, purinyl, quinazolinyl, quinolizinyl, quinolinyl, isoquinolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, azepinyl, diazepinyl, acridinyl and the like. Heteroaryl is also intended to include the partially hydrogenated derivatives of the heterocyclic systems enumerated above. Non-limiting examples of such partially hydrogenated derivatives are 2,3-dihydrobenzofuranyl, 3,4-dihydroisoquinolinyl, pyrrolinyl, pyrazolinyl, indolinyl, oxazolidinyl, oxazolinyl, oxazepinyl and the like.
The term “perhalomethyl” as used herein designates a methyl moiety substituted with three halogen atoms. Non-limiting examples of perhalomethyl are CF3, CCl3, and CF2Cl.
The term “perhalomethoxy” as used herein designates a perhalomethyl linked via an oxygen atom, e.g. —O—CF3, —O—CCl3, and —O—CF2Cl
The term “ring system” as used herein includes aromatic as well as non-aromatic ring moieties, which may be monocyclic, bicyclic or polycyclic, and they encompass moieties with zero, one or more hetereatoms selected from nitrogen, oxygen and sulphur. Non-limiting examples of such ring systems are aryl, C3-8-heterocyclyl and heteroaryl.
The term “heterocyclic system” as used herein includes aromatic as well as non-aromatic ring moieties, which may be monocyclic, bicyclic or polycyclic, and containing in their ring structure one or more heteroatoms selected from nitrogen, oxygen and sulfur. Non-limiting examples of such heterocyclic systems are C3-8-heterocyclyl and heteroaryl.
Certain of the above defined terms may occur more than once in the structural formulae, and upon such occurrence each term shall be defined independently of the other.
The term “optionally substituted” as used herein means that the groups in question are either unsubstituted or substituted with one or more of the substituents specified. When the groups in question are substituted with more than one substituent the substituents may be the same or different.
The term “optionally covalently bound” as used herein means that the substituents in question are either not covalently bound to each other or the substituents are directly connected to each other by a covalent bond. A non-limiting example of such optionally covalently bound substituents is —NR1R2 wherein R1 is ethyl and R2 is propyl which provided that the substituents, ethyl and propyl, are optionally covalently bound may be ethyl-propyl-amino, 1-piperidyl, 3-methyl-1-pyrrolidyl or 2,3-dimethyl-1-azetidyl.
The term “hydrolysable group” as used herein means a group which can be hydrolysed at certain chemical conditions, i.e. an internal covalent bond in the group can be cleaved to give two compounds. A hydrolysable group does not have to be hydrolysed during carrying out the present invention. For instance, the hydrolysable group —C(═X)-L can be hydrolysed to give the products —C(═X)OH and HL, which means that the covalent bond between —C(X) and L is cleaved. Examples of hydrolysable groups are carbamates, esters and amides.
The terms “disease”, “condition” and “disorder” as used herein are used interchangeably to specifiy a state of a patient which is not the normal physiological state of man.
The term “treatment” as used herein means the management and care of a patient having developed a disease, condition or disorder, as well as the management and care of an individual at risk of developing the disease, condition or disorder prior to the clinical onset of said disease, condition or disorder. The purpose of treatment is to combat the disease, condition or disorder, as well as to to combat the development of the disease, condition or disorder. Treatment includes the administration of the active compounds to prevent or delay the onset of the symptoms or complications and to eliminate or control the disease, condition or disorder as well as to alleviate the symptoms or complications associated with the disease, condition or disorder.
The term “effective amount” as used herein means a dosage which is sufficient in order for the treatment of the patient to be effective compared with no treatment.
The term “modulate” as used herein means to influence, i.e. to modulate a parameter means to influence that parameter in a desired way. Examples are to modulate insulin secretion from beta cells and to modulate the plasma level of free fatty acids.
The term “medicament” as used herein means a pharmaceutical composition suitable for administration of the pharmaceutically active compound to a patient.
The term “pharmaceutically acceptable” as used herein means suited for normal pharmaceutical applications, i.e. giving rise to no adverse events in patients etc.